It was a vampire squid that inspired the European winner of this year’s Goldman environmental prize to successfully challenge the devastatingly unsustainable practice of bottom-trawling.

More than a decade before Blue Planet, Claire Nouvian was researching this rare creature – a living fossil that is found 4,000m below the surface of Monterey Bay – for a French television company, when she first realised the extraordinary variety of life and colour on the deep ocean floor.

The joy of that discovery was quickly followed by horror when she realised how quickly this landscape – formed over centuries – was being turned into a desert as a result of industrial fishing.

Deep-sea bottom trawlers drag heavy nets with steel doors and roller gear across the ocean floor, decimating ancient coral, mussel colonies, sponges, sea worms and many species that live long and breed too slowly to replenish their numbers. The technique has been compared to the clear-cutting of forests because the heavy doors – some of which weigh several tonnes and are marketed as canyonbusters– scrape the tops off of seamounts and rugged terrain.

Determined to challenge this, Nouvian switched from journalism to activism, founded the Bloom Association in 2005, and began a campaign that recently resulted in a major policy shift by the European Union.

She describes her strategy as an application of investigative journalism. She first identified the problem, honed in on the causes, interviewed the major players and then sieved through reams of data to expose the ecological and economic flaws of the business.

“Deep-sea bottom trawling applies the most destructive fishing to the most fragile ecosystem,” Nouvian told the Guardian in an interview ahead of the Goldman award ceremony. “The seafloor has intricate features that form over years, like cities. Bottom trawling wipes it out.”

Nouvian initially focused attention on a fishing fleet owned by Intermarché, a French supermarket chain. Her association sifted through years of corporate accounts and discovered that the fleet was chronically unprofitable even with public subsidies. In partnership with other NGOs, they also canvassed former fishing communities in France and the UK to see how fishing port communities were being ruined by industrial trawling.

This was followed by a petition calling on the government to ban a practice that was environmentally destructive and economically unviable. With the help of a viral cartoon on the subject by acclaimed French illustrator Pénélope Bagieu, more than 900,000 people signed up, forcing first Intermarché, then the French and UK governments, then the European parliament and council to agree on restrictions. From June 2016, European fleets have been banned from bottom trawling at depths of more than 800m.

Part of the viral cartoon by Pénélope Bagieu. Photograph: Pénélope Bagieu

Nouvian is now targeting pulse fishing, which uses electric currents to stun fish or induce spasms that force sole and plaice from the sediment.

The European commission banned this practice – along with fishing with poison and explosives – in 1998, but eight years later accepted a Dutch proposal for an exemption for 5% of trawlers to conduct “scientific research” into whether this form of fishing is less destructive than other types of trawling.

Nouvian says 84 Dutch ships have been fitted with electrodes, which is more than 30% of the fleet, and they only started collecting data after Bloom challenged them in 2016.

“This is terrifying. If we electrocute fish, we also electrocute eggs and everything else. All life in a certain space is wiped out. It sounds like science fiction, but it is real.”

But she says it continues on a wide scale because the European commission is failing to enforce regulations while the EU institutions make a final ruling on whether pulse fishing should be prohibited.

Nouvian has called on supermarkets to refuse to stock electric-caught fish but so far in the UK only Waitrose, Co-op and Morrisons have agreed, while Tesco, Sainsbury’s, Asda and Marks and Spencers have not replied. French retailers – who have learned not to cross this formidable campaigner – have been more responsive.

European parliament votes to end electric pulse fishing

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The prize-winner – who complains there is only 20 hours to work in a day – is also working to ban shark-finning in Asia and lobbying the World Trade Organisation and governments around the world to end subsidies for destructive industrial fishing and to give more support to small-scale fishing communities.

“There are way too many big fishing vessels and they are kept afloat with public subsidies. But there are fewer fish so they have to go further, enter deeper waters and take more types of fish,” she said. “We have the means to wipe out other species and us with it, but just because we can it does not mean we have to.”